REVUE DE MICROPALEONTOLOGIE最新文献

Well-preserved Late Cretaceous (early Cenomanian) radiolarians were recovered from two sections in Crimea: Bodrak River and Sel’-Bukhra Mountain sections. Abundant and diverse representatives of order Spumellaria were recognized and studied. Four new radiolarian species: Becus naidini nov. sp., B. tauricus nov. sp., Praeconocaryomma? bodrakensis nov. sp., and Savaryella? nikishini nov. sp. were described. Moreover, stratigraphical ranges of species Archaeospongoprunum sphaericum Bragina, Crucella lata (Lipman), Patellula cognata O’Dogherty, P. verteroensis (Pessagno), Spongodiscus quasipersenex Bragina were exactly defined (their lower limits are expanded to the lower Cenomanian). The upper limit of stratigraphic range of "Cenodiscus" alievi Pessagno is expanded to the lower Cenomanian. Our results suggest that two rare taxa "Cenodiscus" alievi Pessagno (California Coast Ranges) and Spongodiscus quasipersenex Bragina (West Sakhalin Mountains) are reported for the first time in the Tethyan regions.

A Cisuralian (early Permian) radiolarian assemblage, including 12 species of seven genera (Parafollicucullus, Albaillella, Latentifistula, Latentibifistula, Pseudotormentus, Quadricaulis, and Polyfistula) and seven undetermined morphotypes of the genera Entactinia and Trilonche, were obtained from bedded cherts of the Hachioji section in the Ashio terrane, Jurassic accretionary complex, central Japan. One new species Latentibifistula clathrata nov. sp. is described herein. This new species is diagnosed as Latentibifistula with a latticed surface and three coplanar arms of varied length.

On the basis of a research started about 40 years ago for the knowledge of the internal structure and mode of growth of the Larcoidea Radiolaria, this article discusses and describes a series of genera and species of larnacillid radiolarians from two subfamilies: Cryptolarnaciinae and Circodiscinae. Ten genera are discussed, of which 6 are new (Phacolarnacium, Globolarnacium, Pylolarnacium, Sanfiriedellus, Circodiscullus, and Stylotrochellus), and 29 species are discussed, of which 17 are described as new. For all of them have been made sections to know as well as possible their initial structure as base of taxonomy. Special illustrations are presented to suggest horizontal gene transfer for at least one species. A partly changed nomenclature of the structural elements of the microsphere and initial skeleton of these radiolarians is proposed.

Developing a more precise time framework in any hydrocarbon-bearing basin is potentially of great value to geologists and reservoir modelers for better understanding the hydrocarbon reservoir zonation, and identifying unconformities. In the Asmari Formation, which is the most important Oligocene–Miocene carbonate reservoirs in Iran, broad time zonation is generally used based on larger benthic foraminifera (LBF). In this study, the biostratigraphic zonation of the Asmari intra-shelf basin is re- evaluated based on the spatial and temporal distribution of LBF (i.e., different species of Nummulites, Eulepidina, Archaias, Spiroclypeus, Miogypsinoides, Miogypsina, and Borelis) as well as Sr isotope datasets. This research proposes a new zonation to improve time resolution in the Oligocene and explains the effects of environmental factors on some index fossils and the limited range of some key fauna. The newly proposed zonation consists of one biofacies and nine biozones occurring throughout the Rupelian to Burdigalian allowing differentiating Oligo-Miocene stages, and tuning the chronostratigraphic framework of the Oligocene–Miocene deposits. Moreover, based on this new biozonation, regional-scale palaeogeographical maps of the Asmari intra-shelf basin during Rupelian-Burdigalian were officially established.

This article re-evaluates the taxonomy of the radiolarian genus Longtanella Sheng and Wang, based on materials obtained from the Guadalupian (Permian) Gufeng Formation in Anhui, China. This leads to the improved description of two previously introduced species (L. zhengpanshanensis and L. turgida) and the documentation of two additional morphotypes left in open nomenclature (L. sp. A and L. sp. B). Based on the new observations and measurements of Longtanella specimens and co-occurring species of Parafollicucullus Holdsworth and Jones, Longtanella differs from Parafollicucullus by having a turriform, slightly bent test and lacking a clear wing or pseudothorax.

Symbiont-bearing larger benthic foraminifera (LBF) are ubiquitous components of tropical and subtropical carbonate-rich shallow-water habitats and contribute substantially to coral reef accretion and stability. More than 60 species of LBF are currently described from the Indo-Pacific Ocean with the Philippines being recently identified as their potential center of maximum species richness.

The Palawan archipelago, also known as the “last ecological frontier” of the Philippines and a hotspot of biodiversity, attracts a growing number of tourists due to its comparatively intact marine environments and picturesque landscapes. Here, we document and illustrate the species-rich fauna of modern LBF from shallow nearshore habitats in northern Palawan. Sampling covered the northernmost part of Palawan's South China and Sulu Sea coasts including the Calamian Islands group. A total of 24 samples were taken from fore-reef slopes, inter-reef areas, a back-reef, seagrass leaves with a nearby mangrove swamp, and a WW2 shipwreck at depths between 0 to 25 m. We recorded a total of 44 LBF morphospecies, a number that is among the highest reported so far. Heterostegina depressa and Calcarina mayori were identified as the most widely distributed taxa in the study area. We further describe Peneroplis hoheneggeri nov. sp. as a new species of Peneroplis de Montfort. The newly described peneroplid is characterized by single rows of large pits and was previously also documented from Micronesia. Our survey supports the designation of northern Palawan as an exceptionally biodiverse ecoregion with high priority for marine conservation efforts.

Eighteen new ostracod species are recorded from the Maastrichtian-lower Eocene stratigraphic succession exposed at the Kharga Oasis in the Western Desert of Egypt. The new findings include eleven newly erected species, besides seven species recorded for the first time but left in open nomenclature. They have been taxonomically described and compared with nearest known and probably related taxa. The species described are assigned to 10 genera belonging to 9 families. Whereas some of recorded species display relatively long stratigraphic ranges in the studied sections, others display shorter ranges confined to a specific age in the Maastrichtian-early Eocene interval.

A new porcelaneous larger benthic foraminifer, Reticulotaberina jahrumiana new genus and new species, from the latest middle Eocene shallow-water carbonate platform deposits of SW Iran (Jahrum Formation, Zagros Mountains) is described. Its structure is characterized by the development of a thin alveolar layer (exoskeleton) in the marginal area of the chamber lumen and by septula and interseptal pillars (endoskeleton) in the central area. The septula build a network, whereas the interseptal pillars rise from its intersections. The intercameral foramina are concentrically arranged and are intercalated with septula. R. jahrumiana n. sp. displays a strong dimorphism: A-form has a planispiral-uncoiling subcylindrical morphology, whereas the B-form presents a flared shape with oval or compressed outline. The new taxon is included in the Praerhapydioninidae family and is so far known from the south-west of Iran. The age is late Bartonian.